1. Field
The disclosed subject matter relates to a reflector on a vehicle, referred to as a reflex reflector that can receive light from headlights (or other lights sources) from another oncoming vehicle (or other source) and correctly reflect the light in the direction from which the light was emitted, even when the reflector-mounted vehicle is at rest, that is, when the lights are all turned off. This reflector is effective to notify the driver of the oncoming vehicle of the presence of the vehicle at rest.
2. Description of the Related Art
A reflex reflector typically utilizes the property of three-face square mirrors combined together at right angles to reflect light from all of the mirrors such that light returns in substantially the same direction from which the light enters the reflex reflector. A general reflex reflector includes a number of elements each including the above three-face square mirrors, which are arranged in a plane to configure a one-face reflective surface.
In the design of a vehicle, however, for example, part of a light fixture, such as an outer lens may be formed with a curved surface. In this case, the position to which a conventional reflex reflector 90 is attached is not always flat. As exemplified in FIG. 3 in a cross-sectional view of a lens 80 with the reflex reflector 90 formed thereon, the reflex reflector may have a secondary curved surface. In response to this, methods of manufacturing the reflex reflector 90 with a curved reflective surface have been proposed as shown in FIGS. 4-5 (see, for example, U.S. Pat. No. 6,540,202).
As described above, one reflective surface on the reflex reflector 90 is formed as shown in FIG. 3. Namely, faces on the tip of a right hexagonal pin 91 are shaved two by two at a certain angle to the axis of the pin 91 such that the face tips meet at the center of the pin 91. The pin 91 thus formed has three orthogonal square faces, that is, a reflex reflective surface 92 on the pin tip. A certain number of these pins 91 are arranged (bundled) in parallel to configure an original of the one-face reflex reflector 90. A metal film is then laminated on the original by electroplating. Thereafter, the original is mold-released to obtain a molding part. This is the so-called electroforming method for obtaining a molding part having the reflex reflective surface.
Thereafter, the molding part of the reflex reflective surface is embedded in a mold of an outer lens as part thereof to complete a mold of the outer lens provided with the reflex reflective surface. The reflex reflector requires higher mold processing accuracy such as surface accuracy of the reflective surface and angular accuracy between faces. Therefore, the mold is not manufactured by machining such as numerical control (NC) machining, but rather multiface-structured pins are mainly combined together as described above to make the original of the reflex reflective surface. The mold thus obtained is used for molding a transparent resin to yield products.
As described above, the pin 91 has the reflex reflective surface 92 in the minimum unit on the tip. Accordingly, in order to arrange the reflex reflective surface 92 on a curved surface, for example, a dowel 93 having a certain length may be provided between the pins 91 as shown in FIG. 4. Alternatively, a shim 94 having a certain angle may be sandwiched between the pins 91 as shown in FIG. 5. Reference numeral 70 in FIG. 3 conceptually shows the state of two pins when the reflex reflective surface 92 is formed on the curved surface as described above.
In either of the methods of providing the dowel 93 between the pins or sandwiching the shim 94 between the pins as described above, a single pin 91 is around 2-3 mm in width at the opposite side of a hexagon. Accordingly, if the pin 91 is 2 mm and the reflex reflector 90 has an outer diameter of around 100 mm×50 mm, for example, the number of the pins 91 that are used reaches 1000 or more.
Namely, this means that dowels 93, for example, must be attached to many pins 91 as described above which involves a great deal of labor and time, etc. In addition, if the reflex reflective surfaces 92 provided on the associated pins 91 are not assembled at the same angle, variations may arise in the reflexive direction which can create problems. Thus, there is a need for high assembly accuracy, which results in a remarkable increase in cost, time, etc., without completely solving the problem.
If the entire reflex reflective surface is arranged and configured along the curved outer surface of the outer lens, the occurrence of the so-called undercut can not be avoided, which disables mold-releasing. In this case, a solution can be given with the use of a slide mold dividable into pieces that can be released in different directions. The divided portion in this type of mold, that is, the sliding surface of the slide mold suffers a strong frictional force. The molding part of the reflex reflective surface made through the above electroforming method is characteristically weak against the sliding friction. Accordingly, it is not preferable to apply this type of molding techniques on such a structure.
Therefore, if the reflex reflective surface is arranged along the curved surface, the divided portion in the mold is sometimes formed in different shape from the reflex reflective surface, and can be formed as a non-reflexive shape from the viewpoint of mold accuracy even if it is an analogous shape. In addition, the arrangement along the curved surface results in a continuously varying direction of reflexive reflection, which may not achieve a sufficiently effective reflection area depending on the direction of observation.
To solve the above problem, plural plate-like reflex reflectors are arranged along the curved outer lens in a corresponding method. In this case, however, an increase in the number of components causes increase in component costs, assembly costs and management costs. In addition, the above effective area may not be ensured. Thus, the arrangement of the reflex reflective surface along the curved outer lens causes a problem associated with the difficulty in configuring reflex reflective surfaces having a uniform reflexive reflection performance.